POS1294 SAFETY AND EFFICACY OF ADALIMUMAB BIOSIMILAR (AMGEVITA) IN PAEDIATRIC RHEUMATOLOGY PATIENTS
Authors: C. Chen, K. L. Teh, T. Arkachaisri, L. Das, Y. X. Book, S. F. Hoh, X. Gao
Journal: Annals of the Rheumatic Diseases (2022)

Background The approval of biosimilars requires pharmacokinetic studies to prove that there are no clinically significant differences to the originator molecule. These studies are also used to extrapolate additional indications and for different populations including paediatrics. Literature is lacking for the efficacy and safety of biosimilars for paediatric rheumatology conditions. Amgevita, a biosimilar of adalimumab, was approved for use in Singapore on 31 July 2019. It was used in KK Women’s and Children’s hospital (KKH), Singapore from 1 September 2020. Objectives To report the safety and efficacy of adalimumab biosimilar in children at our centre. Methods This is an ongoing prospective, IRB-approved, observation study in a paediatric rheumatology clinic sited within KKH, a tertiary children’s hospital. Patients were reviewed in clinic to determine the need to initiate adalimumab (Amgevita), and completed pre-biologic screening to assess suitability to start. Patients were included if they received minimum 1 dose of adalimumab biosimilar. Safety parameters tracked: allergy, including urticaria, anaphylaxis, severe injection site reactions, rate of new onset infections requiring hospitalization and reactivation of latent infections (e.g., tuberculosis or herpes zoster). Adverse reactions were graded according to CTCAE v5.0. Efficacy parameters were tracked for patients with juvenile idiopathic arthritis (JIA) included JADAS27, JADAS71 and JSpADA. Results From 1 September 2020 to 31 October 2021, a total of 187 of 20mg syringes and 1403 pre-filled 40mg pens were dispensed to 117 paediatric rheumatology patients. Mean age was 14.9 years, 53.9% were male, 70.9% were Chinese and ethesitis-related arthritis (46.1%) was the most common indication. There were 68 (58.1%) biologic naïve patients. Two patients experienced injection-site urticaria which prompted discontinuation (grade 2). One patient reported initial injection site soreness which resolved spontaneously (grade 1). One patient developed latent tuberculosis requiring inpatient management and temporary interruption in adalimumab therapy (grade 3). No other adverse events were reported. Efficacy data was available for 96 patients. Median scores at baseline and at 3-months and 6-months are presented in Table 1. Table 1. Summary of paediatric patients initiated on adalimumab biosimilar (Amgevita) Diagnosis, n (%) Enthesitis related arthritisOf which HLA-B27 positive 54 (46.1)44 (81.5) Polyarthritis 21 (17.9) Extended or persistent oligoarthritis 15 (12.8) Undifferentiated JIA 6 (5.1) Psoriatic arthritis 1 (0.8) Other indications 21 (17.9) Concomitant DMARDs, n (%) Methotrexate 50 (42.7) Sulfasalazine 37 (31.6) *Efficacy, Median (range) Biologic naïve Not biologic naïve Month number 0 3 6 0 3 6 JADAS27 2(0-21.6) 0(0-8.5) 0(0-6.05) 2(0-10.6) 0(0-8.4) 0(0-12.2) JADAS71 2(0-27.8) 0(0-12.0) 0(0-6.08) 2(0-10.6) 0(0-8.4) 0(0-12.2) JSpADA 0.25(0-3.5) 0(0-1.0) 0(0-1.0) 0.5(0-1.5) 0(0-0.5) 0(0-2.0) DMARDs: Disease modifying anti-rheumatic drugs; JADAS: Juvenile Arthritis Disease Activity Score; JSpADA: Juvenile spondyloarthritis disease activity. *Efficacy data only for patients with juvenile idiopathic arthritis Conclusion We report our 14-month experience of using adalimumab biosimilar in a pediatric rheumatology population. Majority of the patients did not report major adverse reactions. Majority of JIA patients responded well when initiated on adalimumab (Amgevita). Rheumatologists should continually monitor patients for latent infections after prescribing biologics including biosimilars. References [1]Scientific considerations in demonstrating biosimilarity to a reference product: guidance for industry. FDA website. Apr 2015. https://www.fda.gov/media/82647/download . Accessed 28 Dec 2021. [2]De Cock D, Kearsley-Fleet L, Baildam E, Beresford MW, et al. Biosimilar Use in Children and Young People with Juvenile Idiopathic Arthritis in aReal-World Setting in the United Kingdom [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). Disclosure of Interests None declared